Computer-aided design (CAD) software allows a user to construct and manipulate complex three-dimensional (3D) models. A number of different modeling techniques can be used to create a 3D model. One such technique is a solid modeling technique, which provides for topological 3D models where the 3D model is a collection of interconnected topological entities (e.g., vertices, edges, and faces). The topological entities have corresponding supporting geometrical entities (e.g., points, trimmed curves, and trimmed surfaces). The trimmed surfaces correspond to topological faces bounded by edges. Hereinafter, the terms vertex, edge, and face will be used interchangeably with their respective, corresponding geometric entities.
A design engineer is a typical user of a 3D CAD system. The design engineer designs physical and aesthetic aspects of 3D models, and is skilled in 3D modeling techniques. The design engineer creates parts and may assemble the parts into a subassembly. A subassembly may also consist of other subassemblies. An assembly is designed using parts and subassemblies. Parts and subassemblies are hereinafter collectively referred to as components.
CAD systems may also support two-dimensional (2D) objects that are 2D representations of 3D objects. Typically, two- and three-dimensional objects are used during different stages of a design process. Three-dimensional representations of a model are commonly used to visualize a model because the designer can manipulate the model in 3D space and visualize the model from any conceivable viewpoint. Two-dimensional representations of a model are commonly used to prepare and formally document the design of a model. Such documentation may include geometric dimensioning and tolerancing (GD&T).
A 2D representation of the 3D model is often referred to as a 2D drawing, or simply, a drawing. A 2D drawing contains one or more drawing views where, in general, each view illustrates the model in a specific orientation (e.g., top, front, or left side view), or illustrates a detail or section view of the model. Typically, the 2D drawing is used to communicate the design to a manufacturing engineer so that the physical object corresponding to the 2D drawing, and therefore, also corresponding to the 3D model, can be built.
Rather than using a 2D drawing to formally document the design of a model, a three-dimensional model may be used as the source of information relevant to documenting, communicating, and specifying product and manufacturing information (PMI). Hereinafter, such practice will be referred to as model-based definition (MBD). MBD is becoming a best practice in design and manufacturing, and may more clearly communicate information relevant to the design and manufacturing process than a 2D drawing (which may be cluttered with various views and annotations). Employing MBD technology, valuable PMI and GD&T may be stored with the 3D model and displayed with the 3D model. SolidWorks® 2015 3D CAD software, available from Dassault Systemes SolidWorks Corporation of Waltham, Mass., enables a user via MBD technology to annotate a 3D model and project the annotations in 3D space with respect to the 3D model.
Additionally, the MBD approach provides more context for manufacturing instructions. Two-dimensional drawings are often confusing not only because the difficulty some may have mentally constructing a 3D object from several 2D representations but also because the 2D drawings may have numerous annotations. The MBD approach removes the need for referencing separate, 2D drawing views. Further, an MBD approach may help prevent mistakes and misunderstandings during the design and manufacturing process, especially since during the design of a product, the design may likely be interpreted by different engineers.
Other fairly recent 3D modeling developments include placing a 3D model in a real world setting via augmented reality (AR), a technology that augments a real-world view with digital images and information. Images of a 3D model can be shown on a heads-up-display (HUD) or on a non-transparent display screen, such as one may find on a mobile device. In addition, real-world objects may be combined with the 3D model on a transparent or non-transparent screen. Thus, a HUD and a display screen can project a compilation of physical objects in the real-world (e.g., via a camera lens) and an image of a 3D model designed using a CAD system.
To add model-based definition annotations (e.g., GD&T) to a 3D model in an augmented reality environment, current state-of-the-art technology superimposes the annotations on an image of a real-world object. This method precludes any interaction with the 3D model in the context of a real-world environment.
Using 3D CAD systems, a model's size and appearance may be rendered as close to realistic as possible. This may be accomplished by adjusting the scale of the 3D model, applying a perspective projection to the 3D model, and using photorealistic rendering techniques to display the 3D model. A method that allows a user to view, create, and interact with MBD data in a real-world setting would further enhance the capabilities of a 3D CAD system with respect to making a 3D model appear as realistically as possible. The design and manufacturing industry would benefit from improved systems with enhanced capabilities that supplement real-world environments with MBD data via augmented reality and enable users to interact with the MBD data in a real-world environment.